"ZFS: A Filesystem for Modern Hardware" at LISA 2009

Richard Elling gave a tutorial on the ZFS filesystem. The tutorial included a complete overview of the filesystem from administrative commands to details of how the data is stored on disk.

The tutorial started off with a brief history of filesytems on Solaris and the design goals behind ZFS. This provided a good basis for the discussion of how ZFS was implemented.

Solaris' previous filesystem, UFS has been around since the 1980's. It was designed for a different set of constraints. Systems had limited memory and processing power, so UFS didn't leverage them very heavily. UFS has also had features bolted on over time. Because of this, UFS has grown unwieldy. ZFS, on the other hand, is being developed in a time where most systems have CPU cycles to spare. Memory is also plentiful with a low acquisition cost. Because ZFS was able to wipe the slate clean and start from scratch, it has been able to avoid some of the common problems associated with other filesystems and volume managers. For example, in other filesystems, the base unit of storage is the disk. There are volume managers that aggregate disks together for the filesystems, but this is a kludge at best. ZFS takes the approach that storage should be treated as a pool. All disks are added to 'zpools' and ZFS handles the tasks formerly performed by volume managers. This fundamental difference give ZFS significant power and flexibility.

The tutorial included a significant amount of material on each configuration parameter for zpools and zfs datasets. It also covered the tools used to manage pools and datasets. Richard reviewed how the data protection schemes available in ZFS differ from traditional RAID levels. This review of the administration tools of ZFS would be a great help for the sysadmin with no ZFS experience. After this tutorial, they would be able to create, configure and optimize ZFS.

Upcoming features like encryption and dedupe were touched upon. Both of these features were a little too fresh to be fully covered in this class. Dedupe was completed today. Encryption is scheduled to be integrated sometime in the fourth quarter of this year.

One of the most valuable parts of the tutorial was the section on performance tuning. It covered tuning for some of the most common use cases such as databases. It also covered the game changing concept of a Hybrid Storage Pool. With HSPs, the sysadmin will be able to take advantage of both SSDs and HDDs in a blazing fast combination that won't break the bank.

The tutorial was complete and thorough. It provided data and analytical tools to allow the sysadmin to make informed decisions about protecting data on ZFS.

I certainly hope this tutorial is available at future LISA conferences. ZFS as a technology is quite young. As ZFS matures and is accepted by a larger audience, there will be a need for sysadmins well versed in its operation. I hope this tutorial will be able to continue to grow and adapt to that requirement.